Engineering p-Band Center of Oxygen Boosting H+ Intercalation in δ-MnO2 for Aqueous Zinc Ion Batteries

In aqueous zinc ion batteries (ZIBs), the H+ intercalation possesses superior electrochemical kinetics with excellent rate capability, however, precisely modulating H+ intercalation has been still challenging. Herein, a critical modification of pre-intercalating metal ions in the MnO2 interlayer (M-MnO2) with controllable p-band center (epsilon(p)) of O is reported to modulate the H+ intercalation. The modulation of metal-O bond type and covalency degree on the average charge of O atom results in optimized epsilon(p) and H+ adsorption energy for M-MnO2, thus promoting the balance between H+ adsorption and desorption, which plays a determinant role on H+ intercalation. The optimized Cu-MnO2 delivers superior rate capability with the capacity of 153 mAh g(-1) at a high rate of 3 A g(-1) after 1000 cycles. This work demonstrates that epsilon(p) could be a significant descriptor for H+ intercalation, and tuning epsilon(p) effectively increases H+ intercalation contribution with excellent rate capability in ZIBs.

Automated summary

A critical modification of pre-intercalating metal ions in the MnO2 interlayer is reported to modulate the H+ intercalation behavior in aqueous zinc ion batteries. By optimizing the metal-O bond type and covalency degree, the p-band center of O (epsilon(p)) can be effectively tuned to promote the balance between H+ adsorption and desorption, resulting in enhanced rate capability. This work highlights the significance of epsilon(p) as a descriptor for H+ intercalation in ZIBs.